1. Field of the Invention
This invention relates to a magnetic alloy suitable for a magnetic head used for high-density magnetic recording.
2. Description of the Prior Art
With a recent increase in demands for achieving higher-density or broader-frequency band magnetic recording, it has been attempted to use in a magnetic recording medium a magnetic material having a high coercive force to narrow the width of recording tracks so that high-density magnetic recording-reproducing can be achieved. Magnetic alloys having a high saturation magnetic flux density Bs are needed as materials for magnetic heads used in carrying out the recording-reproducing on such a magnetic recording medium having a high coercive force. Under such circumstances, magnetic heads comprised of, in part or as a whole, a sendust alloy or a Co-Zr amorphous alloy or the like are proposed.
With a more increasing tendency toward higher coercive force of magnetic recording mediums, however, it has become difficult for the magnetic heads comprised of the sendust alloy or Co-Zr amorphous alloy to attain good magnetic recording-reproducing. A perpendicular magnetic recording system is also proposed, in which a magnetic recording medium is magnetized not in its longitudinal direction but in its thickness direction. In order to successfully carry out this perpendicular magnetic recording system, the tip of the main magnetic pole of a magnetic head must be made to have a thickness of not more than 0.5 .mu.m, so that it becomes necessary to use a magnetic alloy used for magnetic heads that has a high saturation magnetic flux density, even when recording is carried out on a magnetic recording medium having a relatively low coercive force.
Under such circumstances, magnetic alloys mainly composed of iron, as exemplified by alloys of an iron nitride or Fe-Si system, are known as magnetic alloys having a higher saturation magnetic flux density than the sendust alloys or Co-Zr amorphous alloys.
These conventionally well known magnetic alloys with a high saturation magnetic flux density Bs, however, has so large a coercive force Hc that they are unsatisfactory as materials for magnetic heads when used as they are. Hence, a magnetic head with a multi-layer structure is proposed in which a magnetic material with a low coercive force such as a sendust alloy or a permalloy, or a nonmagnetic material such as SiO.sub.2, is used to form an intermediate layer.
In order to give a magnetic head having such a multilayer structure, there are problems that manufacturing steps or cost must be increased and also it is difficult to maintain reliability. In particular, to give a film thickness of several microns or more, it is sometimes required to provide a multi-layer structure of 100 layers or more. There is also a limit to the working range.
For the purpose of solving this problem, the present inventor has proposed that a magnetic alloy with a single layer and a high Bs and low Hc can be obtained using an Fe-N-O alloy. This alloy, however, has the problem that it is not suitable for glass molding.